Dimpling tool



ci. 4, 1949. H. E. van" ET AL 2,483,799

DIMPLING TOOL Filed June 26, 1945' 2 Sheecs-Sheet 1 22 F l6 2 /5- /6 2 36 W N y y 53 HG l6 lllll I l V INVENTORS. HERMAN/V E. v/r A/VD CLARENCE H. KROUT ATTORNEY 0% 1949. H. E. VEIT ET AL I 2,433,799 v DIMPLING TOOL Filed June 26,1945 2 Sheets-Sheet 2 INVEN TORS. HERMAN/V E. VE/7' A ND CLARE IVGE H. If ROU T BY ATTO IVE) Patented Oct. 4, 1949 DIMPLING TOOL v Hermann E. Veit, Towson, Md., and ClarencdH.

Krout, York, Pa., assignorsto The Glen L;

Martin Company, Mid

'tion of Maryland dle River, Md., a corpora- Application June 26, 1945, Serial-No; 601,668

4 Claims.

Our invention relates to an apparatus for forming dimples, and more particularly to an improved dimpling tool including means whereby the depth of the dimple to be formed may be pre cisely controlled,

Our present invention relates to improvements in dimpling tools of the type described and claimed in the copending application, Veit, Method and apparatus for the dimpling of hard metal alloys, Serial No. 548,073, filed August 4, 1944. The tool of the instant invention provides many of the advantages described in connection with the device of said Veit application and has been developed and is utilized for similar purposes.

Our improved dimpling tool also includes means for controlling the final position of the tool body with respect to the top surface of the sheet being dimpled to insure that the spinning tool will move down into the sheet far enough to form an adequate dimple but not so far that the burr remover will cut into the surface of the sheet. The construction is such thatthis has been achieved while retaining the advantages of the tool of the said copending application. i i

7 It is possible for a skilled operator to achieve a careful control of the depth of each dimple with existing dimpling tools, This, however, requires considerable experience in the handling of the tools. When unskilled operators use such tools, variations of several thousandths of an inch in the depth of the dimple, and damage to the surface of the sheet adjacent the dimple by the burr remover, may occur. In. sheet metal work requiring precision and accuracy of the degree involved in the construction of aircraft, and the like, such variations and imperfections lead to excessively high costs, and are to be avoided if possible. 7

To provide equipment suited to use by unskilled operators, drill presses are conventionally equipped with adjustable frame stops to limit the movement of the tool at a predetermined point with respect to the frame. Such apparatus, however, does not stop the movement'ofthe tool at apredetermined point with respect to the surface of a sheet. All large metal sheets possess thick-v ness variation from point to point over their surface. Consequently the various portions of the sheet surface are not on the same. plane. When the conventional drill press frame stop is so ad justed as to produce the desired dimple on the thick .part of the sheet the tool would not at a thinner portion of the sheet come down; far enough to complete the dimple or to removethe burr formed by the dimpling operation. When the frame stop is adjusted-forthe thin portion, the tool would cutaoo deeply-.intothe thicker part. As-a result, ;control arrangements which involve regulatory meansapart from the dimpling tool itself require the skilled operator to make frequent adjustments to' compensate for the variations in the thickness of metal being worked. The unskilled operator being unfamiliar with the thickness variations-inherent in sheet stock and lacking the experience thatwould provide the proper feel of the =wprking tool finds it difficult to form acceptable dimples.

It is an object ofour invention to provide a spindimpling tool having dimple control means integral therewith whereby the operator may produce -uniform',:acceptable dimples regardless of the thickness variation in the sheet being worked; q '1 It is a further object of our. invention to provide a tool for forming a dimple about a hole in sheet metal that includesa metal spinning element adapted to be advanced into the sheet to spin 'a conical dimple about the hole and trim the burr occasioned by the spinning, and wherein means are provided to insure that the tool advance will complete the dimple and trim the burr flush with the surface'of the sheetwithout being advanced to'a point-where the burring operation penetrates the surfaceofthe sheet; 1

It is another'object ofour invention to provide a tool for forming a dimple about'a hole in sheet metal that includes ametal spinning element adapted to be advanced into the sheet to spin a conical dimple about th hole} and burr trimming means surrounding'said metal spinning element adapted to be advanced with said spinning element wherebysaidtrimming' element will trim the burr occasioned by the spinning. and wherein control means are provided toinsure that the tool advance will completeahe dimple to a predetermined depthjin the sheet and will trim the burr, flush withthesurfaceof the sheet without permitting the trimming element to penetrate the surface of the sheet, 7 v 7 It is another object vofol-lr lnventionto provide a tool accordingto, thepreceding object wherein the said control means includes a pressure pad mounted foraxial. and rotarymovement relative to said spinningandtrimming means and cooperating stops on the. toolbody and pressure pad limiting the relative axial movement between the pressure. pad and I tool he dy.

It is another-objectpf our invention to a. tool according t the preceding object wherein appear more fully in the following descriptionand in the accompanying drawings, wherein;

Figure 1 is a cross sectional view of our 'dimpling tool with the sheet tobe-dimpled in place on the anvil, and with the tool'in raised position;

Fig. 2 is a similar view showing the spinning element lowered with respect to the pressure pad;

Fig. 3 is an enlarged end view of the spinning and burring elements of the tool;

Fig. 4 is an enlarged fragmentary perspective view showing the spinning, burring, and pilot elements of the tool; and

Fig; 5 is an enlarged detail in perspective of the adjusting collar of our dimpling tool.

A preferred embodiment of our invention comprises a rotating tool body 6 having at one end a shank 1 adapted to be secured to and driven by the chuck 8 of a conventional'drill pressfand an anvil9 including a depending centering boss [0 held in a suitable fixture, or vise, H in alignment with the axis of the tool body 6 as shown-in Figure 1. The lower end of the tool body 6 is provided with an axial bore i2- interiorly threaded to receive the threaded shank 13 of a metal spinning element l4. At its lower end the metal spinning element i4 is formed witha'plurality' of radial ribs (see Figs. 1, '3and 4), each having a rounded outer edge, to work the metal of the dimple, as described in the copending application-,Serial No. 548,073. The extreme tip of the spinning element I4 is formed to function as apilot l6. Surrounding a'portion of the spinning element which extends below the tool body 6, and in threaded engagement with the spinningelement, is a burrer H formed at its lower end with cutting teeth 18.

Shims of varying thickness may be inserted between the spinning element i4 and the top of the bore 12- to accommodate adjustment of the spinning element :andburrer occasioned-by wear and sharpening of the teeth I8. A shim I9 is shown abutting the end of shank l3 to-prevent further movement into the threaded bore l2 due to axial pressure and turning of the tool body. Whenthe cutting teeth l8 become worn or shortened by re-shar-pening it is necessary to move the spinning element 14 upwardly in relation to the burrer H in order to preserve the proper spacing between their working edges. Consequently the Ishim l9 would in'that event be replaced by a thinner one. An aperture 2!] is provided in one side of the burrer I! to accommodate a spanner wrench whereby the burrer may be tightened on the spinning element 14. A slidablymounted cylindrical pressure pad 21 is provided for the major portion of its length with an axial bore which is .adapted to [receive the burrer l1! and the adjacent portion of the tool body 6. The pressure pad is provided with a concave end surface 22, which cooperates with the convex anvilysurface 23 to flex the sheet metal slightly in a direction opposite that of the dimple itself to obtain the advantages of the arrangement shown and described in Veit patent, No; 2,288,378, granted June 30, 1-942. The pressure pad 2i is urged downward- 1y by a spring 24 extending from the shoulder 25 on the tool body 6, and to insure that the pressure pad will not be driven by the tool body as the pad engages the work sheet W, an upper thrust bearing 32 and a lower thrust bearing 40 are provided to effect free rotation between the The -'end-=perticn of the tool body 6 'adjacent the shank I is threaded to receive an interiorly threaded collar 26 which is adapted for adjustable movement on the threaded portion of the tool body. The collar 26 is shown in detail in Figure5. -Tofprevent the rotation of the collar "onfthe ree bc'tly -after its adjustment, the coliar' lfi"isSplitbrfbne side, as at 27, and may be clamped 'onto thetool body 6 as by a threaded bolt beinepassedthrough a hole 28 which is cut through portions of the collar on both sides of the"br'eak 21. A notch 29 may be cut in the collar to provide working surface for adjusting and securing Ofjthe belt.

-=-A 'sleeve' 30'sfiiouiids the tooibedy-and is secured at eneend td the pressure-pad 21' as by screws 3 I r The sleeve is auteur-a at- (W-adjacent its end to receive the testament-pressure pea 2i, thereb rermmg a mew secure and ri id I b nd between the' sleeve and the 1 pad. To limit the" axiarnevemest 0f the sleeve-and pressure *pad' with-respect to the 't'o'ol bbdySt/he sleeve 3 ilisprovided diacent its oppesite end with an *interiorly eictending ldge 34 arranged to provide; a seatia'l ro!- bnter thrust bearing 35. When--thetool body -is*raised iree" bfthewoi'k sheet (Fig. 1) Y *the' 0611a 26 is' spaced a short distance from the topbf fiter thriist bearing 35,- this 4 distance deis'ndirig' 'bn the adjustment of the collar 26 on shank I. """Wi'ien "the=-t'o'ol body is in i its iowerd staircase-nave to the pressure pad (Fig; 2)" the wise 'fl bears an euter thrust bearing 35.

'As the than: 8 is i the entire? assembly moves toward the W to be dimpled, and the bilOtWG-htrWhi'fi I s'rivetnme'in-the work sheet. The spring 4 -i1rges-- the'-pressure pad 2f against the ca'iiially or the" rivet hole, therebys bpp s the -tin'mnger thepad. The sheet i's' first? lieldand slightly upwardly' around the-= edges 'of -the rivet hole 'bythe cooperating rsces er me pressiire padand=-the ahvil,"to" elimina t -nepression whicu wouia otherwise rom the' ares-adjacent "the dimple. As the downward movement -""-"cbhti'nued the spring 24 is came essefi-and th' ribs l5 of the meta1 el iih't ii -arid the teth -fi fl bf the burrer H ev vertically hiough the opening'in'the" *2! tdbhgage the u permost =siirface of the she'et' area 1 be dimmed. The sheet stock forming the dimple is pregressi'v'ely wdrkedi'ntdth di"-'recess" '36bf the anvil 9. ln-the event afiiirr 1S- ermea attne upper edge 0f the the eIn'ientL- the rotating lflbf the"btt'rrei H "remove it.

ex teht bf theinov'rfient 'oftht'o'ol body, spinning liilht and bfirr'er with relation to the pian-un pe is remea by the relationship between the upper-sin"faee' bf*ledge star the sleeve so-and 5 ori the tool body" 6,. When" the tool reeves dewnwardly through the-sleeve theinfnirrl', the collar 26 contacts the rarest bearing as runner down-ward msvemeht of the tool body is -prevented. i byiiinifiiig'the relative movement between the tboi btuy aea she pressure pad and sleeve the depth of 'bhe dimple-is accurately controlled--within narrew-*- -li&nits -regardless of variations in work sheet thickness. The extent of movement which is permitted between the thrust bearing 35 and the collar 26 may be varied, by raising or lowering the collar 26 on the tool body 6.

Preferably shank l! is provided with an enlarged unthreaded base portion 38 formed slightly less in diameter than the diameter of tool body 6. Indicia 39 may be placed on said base portion 38 and an index line may be so positioned on the top of the collar 26 as to show in fractions of an inch the displacement of the pressure pad sleeve with respect to the tool body. The user may thus determine with micrometer exactness the character of the dimple to be produced and assure removal of any burr formed adjacent the dimple.

If it is desired the sleeve 30 may be prevented from rotating relative to the tool body 6 by a laterally extending member secured to the sleeve that engages a stop on the dimpling tool standi With the use of our invention it will be appreciated that the depth of the dimples will be the same regardless of variations in the thickness of the sheet being worked and that no skill is required to consistently obtain uniform dimples.

Our invention is capable of many modifications within the scope of this specification and is not to be limited to the precise arrangement shown nor otherwise than as set out in the following claims.

We claim:

1. A tool for dimpling sheet metal stock comprising an anvil having a conical recess and a coaxial pilot bore, means adapted to be moved toward and away from said anvil including a pilot to center the stock with respect to said bore, a metal spinning member rotatable about the axis of said pilot to spin the stock to be dimpled into the recess of said anvil as the pilot is advanced with respect to said bore, a metal cutting means placed radially relative to and carried by the spinning member for rotation therewith to trim the burr at the juncture between the surface of the sheet stock and the stock spun into the anvil recess, a pressure pad journaled on the spinning member, and means on the spinning member and pad adapted to limit the movement of said spinning member toward said anvil and thereby control the amount of spinning of the stock.

2. A tool for dimpling apertured sheet metal stock comprising an anvil with a convex surface having a conical recess and a coaxial pilot bore, means adapted to be moved toward and away from said anvil including a tool sleeve formed with an interiorly extending ledge spaced from one end, a tool body adapted for rotatable mounting in said sleeve having a shoulder adapted for engagement with said interiorly extending ledge of the sleeve with one end of said tool body formed for connection to a rotative driving device and the other end thereof provided with an element receiving bore, an apertured pressure pad mounted as an extension of said sleeve having a concave bearing surface aligned with the convex surface of the anvil, spring means spaced between said shoulder of the tool body and the pressure pad arranged to urge the tool body shoulder into contact with said ledge, a metal spinning means mounted in said bore end of the tool body comprised of a, work centering pilot aligned with the anvil pilot bore and a conical spinning element formed with a plurality of radial ribs adapted for uniform engagement with a metal sheet stressed over the anvil for spinning metal of said sheet into the conical recess of said anvil, a burr removing element mounted on the tool body for rotation adjacent the spinning element, an adjusting means mounted on the tool body having a lockable collar spaced from the tool sleeve and adapted for locked engagement with the tool body to limit axial movement of said tool body relative to the sleeve.

A tool for forming a conical dimple about a hole in sheet metal comprising a tool body formed at one end for connection to a rotative mechanism with the other end thereof provided with a ribbed, conical metal-spinning element, a burrremoving element carried by the tool body having cutting teeth normal to the axis of the tool body arranged at the outer end of the ribs of said metal-spinning element and adapted to trim flush with the surface of the sheet being dimpled a burr occasioned by the spinning, and means to control the movement of said tool body toward the surface of the sheet, said control means comprising a pressure pad mounted for axial and rotary movement relative to said spinning and burr-removing means, cooperating stops on the tool body and pressure pad limiting the relative axial movement between the pressure pad and tool body, and regulating means on the tool body whereby the stop on the tool body may be adjusted to vary the limits of said axial movement.

4. A tool for forming a conical dimple about a hole in sheet metal comprising a tool body formed at one end for connection to a rotative driving mechanism and the other end provided with a ribbed, conical metal-spinning element, cutting means mounted on the tool body for rotative movement with the spinning element to provide a circular cutting path adjacent said metalspinning element so as to cut oif a burr, occasioned by the spinning, flush with the surface of the sheet of metal being dimpled, and means to control the movement of the tool body toward the sheet comprising a pressure pad mounted for axial and rotary movement relative to the tool body, said pad mounting including bearings providing for free rotation of the tool body within the pressure pad, and cooperating stops carried by the tool body and the pressure pad and arranged to limit the relative axial movement between the pres-sure pad and tool body whereby the advance of the tool body toward the surface of the sheet is controlled by said stops.

HERMANN E. VEIT. CLARENCE H. KROUT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 14,878 Miller et al. May 13, 1856 173,808 Nugent Feb. 22, 1876 245,678 Weaver Aug. 16, 1881 2,288,378 Veit June 30, 1942 47 Grcenbaum Jan. 12, 1943 

